JP2892478B2 - Antibacterial water-absorbing sheet or film - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a water-absorbing sheet or film having antibacterial properties.

(Prior Art) Various methods have been studied as methods for imparting antibacterial properties to organic polymers. Among them, JP-A-58-7361
Japanese Unexamined Patent Application, First Publication No. H10-163, discloses a method of kneading a zeolite holding a metal having an antibacterial action into an organic polymer and molding it.
JP-A-63-139556 discloses an antibacterial water-absorbing sheet or film made of zeolite, a water-absorbing resin and a film-forming resin, which hold metal ions having an antibacterial action by ion exchange. All of these methods utilize the excellent adhesion, adsorption and ion exchange capabilities of zeolite, and attach antimicrobial metal ions to zeolite, hold them by adsorption or ion exchange, and knead them into organic polymers. To use. The method of holding antimicrobial metal ions on zeolite by adhesion or adsorption has the advantage that metal ions can be held by a simple method and the amount of the metal ions can be changed over a wide range, but the structure of zeolite when held in large amounts can be reduced. Damaged, its porosity, specific surface area is reduced,
When the holding power is weakened and kneaded into a polymer, the metal ions may be released from the zeolite over time, deteriorating the antibacterial effect and its persistence, and causing unexpected deterioration due to the released metal ions. And have the drawback that they may suffer from phytotoxicity. On the other hand, in the case of a water-absorbing sheet, the sheet absorbs water, and thus, when a zeolite holding metal ions by adhesion or adsorption is used as an antibacterial material, the above-mentioned disadvantages of the metal ion-holding zeolite are more likely to appear. Therefore, in Japanese Patent Application Laid-Open No. 63-139556 for water-absorbing sheets or films, in order to eliminate these drawbacks, the type of zeolite used and the amount of metal ions to be retained are limited, and a method for retaining metal ions is used. It states that the method should be limited to the ion exchange method. For this reason, the antibacterial water-absorbent sheet or film according to JP-A-63-139556 can be used for a relatively long time relatively safely, but it is still possible to avoid elution from the sheet or film with a very small amount of metal ions during use. Absent. Therefore, when silver is used as the antibacterial metal, discoloration occurs with time, and the antibacterial property also decreases. The production of such an ion-exchanged zeolite is also a troublesome problem.

(Problems to be Solved by the Invention) As described above, the antibacterial water-absorbing sheet or film disclosed in JP-A-63-139556 requires a complicated method for producing an antibacterial zeolite used as a material, and also has an antibacterial metal ion. Although the dissolution of the compound is extremely small, the dissolution by the ions eluted with time causes the antimicrobial activity to slightly decrease. For example, when silver is used as the antibacterial metal, the discoloration occurs over a long period of time and the antibacterial power is reduced. An object of the present invention is to provide an antibacterial water-absorbent sheet or film that does not exhibit such disadvantages, for example, does not cause discoloration even when silver is used, and hardly reduces the antibacterial activity. Is an antibacterial water-absorbing sheet which can be easily produced, dissolves an antibacterial metal remarkably less than ion-exchanged zeolite, and has a strong antibacterial activity by using an antibacterial metal support in place of the antibacterial zeolite in JP-A-63-139556. Or a film is provided.

(Means and Actions for Solving the Problems) In order to achieve the above object, the present invention discloses Japanese Patent Application Laid-Open No. 63-13 / 1988.
Instead of the antibacterial ion-exchanged zeolite used in JP 9556, a calcined product of a calcium-based ceramic carrying an antibacterial metal or metal ion is used. The calcium-based ceramic used in the present invention is calcium phosphate, calcium carbonate, calcium silicate and hydroxyapatite, the antibacterial metal or metal ion is silver,
It is selected from metals selected from copper and zinc or ions thereof, and hydroxyapatite as ceramics, and silver and zinc as antibacterial metals or metal ions are particularly preferable. Hydroxyapatite
It has a composition of Ga ₁₀ (PO ₄ ) ₆ (OH) ₂ and is a main component of bone,
It has good affinity with biological components and organic substances, strongly adsorbs various organic substances, and has ion exchange ability, so it is most suitable as ceramics used in the present invention, but it is stoichiometric.
The synthesis of hydroxyapatite with a Ca / P molar ratio involves certain difficulties. However, a hydroxyapatite mixture having a Ca / P molar ratio of 1.4 to 1.8 is easily synthesized,
Such a synthetic product can be used in the present invention as a ceramic like hydroxyapatite. The antibacterial ceramic used in the present invention may be prepared by coexisting a water-soluble salt of an antibacterial metal during the production of the ceramic by a conventional method, or after thoroughly treating a solid obtained by treating the ceramic with an aqueous solution of an antibacterial metal salt and then washing the solid with water. It can be dried, calcined at a high temperature, preferably 800 ° C. or higher, and then finely pulverized. For example, in the process of synthesizing hydroxyapatite from calcium hydroxide solution and phosphoric acid by a conventional method, the solid obtained by coexisting a water-soluble salt of an antibacterial metal is washed with water, dried, calcined, and finely pulverized to obtain antibacterial properties. Obtain hydroxyapatite. Alternatively, hydroxyapatite is added to an aqueous solution of an antibacterial metal salt, and after stirring, a solid is collected, washed with water, dried, calcined, and pulverized to obtain an antibacterial hydroxyapatite. Other antibacterial calcium-based ceramics can be easily obtained in the same manner. The amount of metal or metal ion supported on these ceramics can be arbitrarily selected, but if the amount is large, the structure of the ceramic used changes, the supporting force is weakened, and the supported metal or metal Since large amounts of ions are released from the ceramics and may cause unexpected chemical damage, large amounts of the ions should be avoided. Due to the structure retention and antibacterial properties of the ceramics, the loading is 50% by weight or less, preferably 30 to 0.001% by weight.

The obtained antibacterial ceramic is used after being pulverized into fine particles of, for example, several microns to several tens of microns or several hundreds of microns depending on the use. The water-absorbing resin to be mixed with such antibacterial ceramics is a graft polymer of starch / acrylate, a carboxymethylcellulose crosslinked product, a vinyl alcohol / acrylate copolymer, a polyacrylonitrile hydrolyzate, a crosslinked polyacrylate, It is arbitrarily selected from a modified polyvinyl alcohol, an acrylate polymer, an acrylate / acrylamide copolymer or an isobutylene / maleic anhydride copolymer, and other water-absorbing resins. The amount is 0.01 to 50% by weight of the antibacterial ceramic and 10 to 80% by weight of the water-absorbing resin based on the weight of the obtained sheet or film, especially 0.1 to 10% by weight of the antibacterial ceramic and 10 to 60% by weight of the water-absorbing resin. It is preferable. In addition to these components, any film-forming resin commonly used for making a sheet or a film, for example, a PVC resin, an ethylene-vinyl acetate resin, a urethane resin, an acrylic resin, a silicone resin, a natural rubber, a synthetic rubber, and the like are used. You.

Since the antibacterial ceramic of the present invention has an antibacterial metal salt supported on the ceramic and then fired at a high temperature, preferably at 800 ° C. or higher, the ceramic shrinks, and the supported metal salt is converted into a metal or metal ion. Change,
The bonding strength to the ceramics is strengthened, and no metal or metal ions are released into the aqueous phase when absorbing water. For this reason, the water-absorbent sheet or film does not deteriorate for a long time,
Maintains the original antibacterial activity and does not cause phytotoxicity during use.

 Hereinafter, the present invention will be described specifically with reference to examples.

Example 1 Production example 1 of antibacterial calcium-based ceramic used
1. Production of antibacterial hydroxyapatite 1.0 kg of hydroxyapatite in 10 l of distilled water, silver nitrate
32 g and 69 g of zinc nitrate are added and stirred. The product is washed well with distilled water, dried, calcined at 1200 ° C and crushed to reduce silver to about 2
% And about 1.5% of zinc were obtained (1-1).

Example 1-2. Preparation of antibacterial tricalcium phosphate 1.0 kg of tricalcium phosphate and 30 of silver nitrate in 10 l of distilled water
g and 45 g of zinc nitrate are added and stirred. The product is washed well with distilled water, dried, calcined at 1100 ° C and crushed to reduce silver to about 0.5
%, And about 1% of zinc carrying antibacterial tricalcium phosphate (1-2).

Example 1-3. Preparation of antibacterial calcium carbonate 1.0 kg of calcium carbonate and 0.01 g of silver nitrate are added to 10 l of distilled water and stirred. Wash the product well with distilled water, dry, 80
It was baked at 0 ° C and pulverized to obtain an antibacterial calcium carbonate carrying about 0.0001% of silver (1-3).

Example 1-4. Preparation of antibacterial calcium silicate 1.0 kg of calcium silicate, 180 g of silver nitrate, and 200 g of copper nitrate are added to 10 l of distilled water, and the mixture is stirred while boiling. The product was thoroughly washed with distilled water, dried, calcined at 1200 ° C., and pulverized to obtain an antibacterial calcium silicate carrying about 10% of silver and about 5% of copper (1-4).

Example 2 30% by weight of an acrylic acid / vinyl alcohol copolymer, 65% by weight of an ethylene-vinyl acetate copolymer and 5% by weight of the antibacterial calcium-based ceramic produced in Example 1 were mixed and kneaded with a mixer at a processing temperature of 120 ° C. Then, four 1 mm-thick sheets containing the respective antibacterial calcium ceramics were obtained by a heat press machine.

Comparative Example A sheet having a thickness of 1 mm containing an antibacterial zeolite was obtained in the same manner as in Example 2 except that a commercially available antibacterial zeolite (zeomic, 2% of silver) was used instead of the antibacterial calcium-based ceramic.

Example 3 Metal ion elution test 1 g of each of the antibacterial calcium ceramic obtained in Examples 1-1 to 1-4 and the commercially available antibacterial zeolite (denoted as A) was added to 100 ml of distilled water, and stirred for 30 minutes. The metal ions in the solution were measured using an atomic absorption spectrophotometer, and the elution amount was determined.

This shows that the amount of metal eluted from the calcined antibacterial calcium-based ceramics is significantly smaller than that of the antibacterial zeolite.

Example 4 Discoloration Test (1) A calcined antibacterial zeolite carrying 1% by weight of silver and a carrier zeolite; a zeolite ion-exchanged with 1% by weight of silver and a carrier zeolite were each left in a room for 6 months, and the change in white color was measured. did.

From the above results, it can be seen that even if silver-containing hydroxyapatite (silver, 1% -containing) is left indoor for 6 months, no discoloration occurs. The silver-containing zeolite that elutes a small amount of Ag ions was severely discolored and a large decrease in whiteness was observed.

(2) The antibacterial hydroxyapatite-containing sheet obtained in Example 1-1 and the antibacterial zeolite-containing sheet obtained in Comparative Example were left in a room. The antibacterial zeolite-containing sheet showed slight discoloration after half a year and a considerable discoloration after one year, but the antibacterial zeolite-containing sheet did not show discoloration after one year.

Example 5 Antibacterial Activity Test The four types of sheets prepared in Example 2 were cut into 5 × 5 cm, and after absorbing water, Escherichia coli bacteria solution was sprayed to measure the antibacterial activity against Escherichia coli.

Sample 1-1 means a sheet containing the antibacterial calcium-based ceramics manufactured according to Example 1-1.

(Effect of the Invention) Since the antibacterial calcium-based ceramic used for the water-absorbing sheet or film does not elute the supported metal or metal ion at the time of water absorption, the deterioration due to the eluted metal ion is prevented by the water-absorbing sheet or film according to the present invention. It does not suffer from film and has the same antibacterial activity as a conventional antibacterial water-absorbing sheet or film.

Continuation of the front page (72) Inventor Hideo Mitsuyama 2-11-10 Tsukiji, Chuo-ku, Tokyo (Tsukiji Chuo Building) Sangi Co., Ltd. (58) Field surveyed (Int. Cl. ⁶ , DB name) A61L 2 / 16 A01N 59/00-59/26 C08J 5/18

Claims (5)

(57) [Claims] 1. A fired product of an antibacterial calcium-based ceramic compound carrying at least one metal and / or metal ion selected from the group consisting of silver, copper and zinc, a water-absorbing resin and a film-forming resin. Antibacterial water-absorbing sheet or film. 2. The content of the antibacterial calcium-based ceramic and the water-absorbing resin is based on the weight of the water-absorbing sheet or film.
The water-absorbent sheet or film according to claim 1, wherein the content is 0.01 to 50% and 1 to 80%. 3. The water-absorbent sheet or film according to claim 1, wherein the calcium-based ceramic is hydroxyapatite. 4. The method according to claim 1, wherein the firing temperature is 800 ° C. or higher.
To (3) the water-absorbent sheet or film of any one of the above. 5. The water-absorbent sheet or film according to claim 2, wherein the metal and / or metal ion is silver and zinc.